If we assume "half a day" is 4 hours, and 500 pounds. That's 125 pounds per hour. Which isn't the worst rate. Assuming it's actually capped at 4 hours and we all know that if it's your dad's friend, this is not going to be a set and forget kind of thing. So that 4 hours quickly becomes 10. And suddenly you're down to 50 pounds per hour. And then if it's actually static and simple and good, you still have high odds of getting insane feedback demanding changes to make it worse. A motherfucking website would actually be the best option, but wouldn't get you paid. At that point youre just doing it for the lols.

But ultimately, this isn't even about the rate or how much time this will take. this whole scenario depends heavily on the son here. Is the son unemployed and living in dad's basement for free? Then yeah. Sorry, he should probably take any work he can get for any rate he can get. His dad gets a lot more say in how things work financially if the son is relying on him financially. But if the son is already working a full time job and living in his own house? Then no, I don't care what the rate is. Don't commandeer other people's time. Don't make deals that people haven't agreed to. Come to me with opportunities, not demands.